Pipe X can fill a tank in 60 hours while pipe Y can fill the tank in 72 hours. Both pipes are opened together for 20 hours. How much of the tank is left empty?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. .
Pipe X can fill a tank in 60 hours while pipe Y can fill the tank in 72 hours
L.C.M(60, and 72) = 360
The efficiency of X = 360/60 = 6 units
The efficiency of Y = 360/72 = 5 units
Both pipes are opened together for 20 hours
Tank filled in 20 hrs = 20 × (6 + 5) = 20 × 11 = 220
Remaining units = 360 - 220 = 140 units
Remaining tank = 140/360 =